Nathaniel w



N. W. PRATT.

FURNACE FOR STEAM GENERATORS.

(N9 Model.)

'No'. 323,883. Patented Aug. 4, 1885.

INVBNTOR 7 who ATTORNEY WITNESSES I n, PETERS. Phmo-Lilhognpher, Washington. a, c.

NITED STATES PATENT OFFICE.

NATHANIEL W. PRATT, OF BROOKLYN, ASSIGNOR TO THE BABOOUK & WILCOX COMPANY, OF NEW YORK, N. Y.

FURNACE FOR STEAM-GENERATORS.

SPECIFICATION forming part of Letters Patent No. 323,883, dated August 4, 1885.

Application filed March 27, 1885.

To all whom it may concern:

Be it known that I, NATHANIEL W. PRATT, a citizen of the United States, residing at Brooklyn, in the county of Kings and State of New York, have invented a new and useful Improvement in Furnaces for Steam-Generators, of which the following is a specification, reference being had to the accompanying drawings, in which- Figure l is a side elevation, partly in section, of a steam-generator embodying my invention; Fig. 2, an enlarged transverse view of the roof of the furnace; Fig. 3, a similar view of a modification of the roof structure, and Fig. 4 a side-view ofFig. 3.

Similar letters of reference indicate corresponding parts in the several figures.

The invention consists in constructing the roof or crown of the furnace of fire-brick or similar material, supported by the heatingtubes, a portion of said roof being made solid and the remainder constructed with openings of equal or gradually-increasing size, as hereinafter particularly referred to.

In the drawings a stationary boiler is represented in Fig. 1,in which a furnace, a, inclined heating tubes 1), steam drum 0, and other adjuncts common to such boilers are shown.

In the type of boiler shown, and to which my invention is applied, the course of the products of combustion from the furnace at is ndicated by the arrows, Fig. 1, which I produce by filling the spaces between the row of tubes adjacent to the furnace with fire-brick for a portion of the distance from the front rearward, as shown at d, and partially filling (No model.)

the remaining spaces with the same or similar substance, the openings left, as shown at h, by preference gradually increasing in size toward the bridge-wall i.

The fire-brick or other similar material may be placed either in transverse lines, as shown.

in the enlarged View, Fig. 2, or in a staggered manner, as shown in Fig. 3, the latter showing openings of uniform size that may be adopted, if desired.

In order to direct the course of the heated gases to the front of the upper rows of the tubes b, a curtain, g, and cover or hood m are also provided. The advantage in the construction of the crown or roof shown will be readily appreciated. If the gases generated near the front portion of the furnace were allowed a direct escape, they would render but little heating elfect; but when retained in contact with the incandescent fuel and carried to the rear of the furnace in the inannerindicated the advantage is manifest.

Having thus fully described my invention, what I claim, and desire to secure by Letters Patent, is

A furnace crown or roof composed of firebrick or similar substance, supported by the adjacent heating-tubes, the front portion of said crown or roof made solid and the rear portion made with openings of equal or in;

creasing size toward the bridge-wall, as set forth.

NAT. W. PRATT.

' Witnesses:

C. W. FORBES, AUG. OREVELING. 

